SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an undulant stack demonstration appearance can demonstrate two stack processes of wave well.
The utility model discloses a realize above-mentioned purpose, adopt following technical scheme:
a wave superimposition demonstrator comprising:
the device comprises a fluctuating signal generating circuit, a signal synthesizing circuit, a phase modulation circuit and three-way signal output interfaces; defining three signal output interfaces as a first output interface, a second output interface and a third output interface respectively;
the signal output end of the fluctuation signal generating circuit is respectively connected to the first output interface, one signal input end of the signal synthesizing circuit and the signal input end of the phase modulating circuit;
the signal output end of the phase modulation circuit is respectively connected to the other signal input end and the second output interface of the signal synthesis circuit;
and the signal output end of the signal synthesis circuit is connected to the third output interface.
Preferably, the fluctuation superposition demonstrator further comprises an oscilloscope;
the first output interface, the second output interface and the third output interface are respectively connected to the oscilloscope through signal cables.
Preferably, the wave signal generating circuit includes a sine wave signal generating circuit or a cosine wave signal generating circuit.
Preferably, the signal synthesis circuit is an adder circuit.
Preferably, the phase modulation circuit employs a variable phase shift phase modulation circuit.
Preferably, the wave superposition demonstrator further comprises a housing;
the wave signal generating circuit, the signal synthesizing circuit and the phase modulation circuit are all positioned in the shell;
and the shell is provided with a through hole corresponding to the positions of the three signal output interfaces.
Preferably, the phase modulation circuit is configured with a phase modulation knob;
a knob hole is also arranged on the shell at the position corresponding to the phase modulation knob, and the phase modulation knob extends out of the knob hole.
Preferably, the fluctuation superposition demonstration instrument further comprises a power supply circuit positioned in the shell;
the power supply circuit is connected with the fluctuation signal generating circuit, the signal synthesizing circuit and the phase modulation circuit through the power supply circuit.
The utility model has the advantages of as follows:
as above, the utility model provides an undulant stack demonstration appearance, this demonstration appearance can demonstrate well two stack processes of wave, shows respectively on oscilloscope through the signal waveform with two way wave signal and after undulant stack promptly, and the result before the stack of two lists of waves of being convenient for, after stack process and stack lets the student obtain directly perceived cognition to undulant stack principle.
Detailed Description
The basic principle of the utility model is that:
the principle of superposition of wave motion in physics is described as "the vibration of several trains of waves at any point in the meeting region, which is the vector sum of the vibration displacement caused at that point when each train of waves exists alone".
Interference is an important characteristic of wave motion, and its theoretical description is "the phenomenon that when two trains of waves with the same frequency, parallel vibration directions, the same phase or constant phase difference meet, the vibration is intensified in some places and weakened in other places".
When teaching is carried out on the part of theoretical courses, teachers mostly design two trains of waves according to theories, display superposition processes and results of the waves in the form of pictures or animations, and can only enable students to form abstract impressions due to over-theorization, so that the students cannot obtain visual cognition.
In addition, the existing standing wave experiment can only demonstrate the result of standing wave formation, but cannot demonstrate the processes before and during synthesis.
The wave superposition theory is simplified, two lines of waves are provided, the amplitudes and the frequencies of the waves are the same, a certain phase difference exists, and the expressions are as follows: y is1=Acosωt;y2=Acos(ωt+φ0);
Wherein A is the amplitude of the wave, ω is the angular frequency, φ0Is the phase difference of the two trains of waves.
The fluctuation expression after superposition is as follows:
the fluctuation expression after the superposition shows that the amplitude and the phase of the waveform after the superposition follow phi0May vary.
Based on the above technical principles, the following detailed description of the present invention is made with reference to the accompanying drawings and the specific embodiments:
this embodiment describes a wave superposition demonstrator. As shown in fig. 1 and fig. 2, the fluctuation superposition demonstration instrument includes a fluctuation signal generation circuit 1, a signal synthesis circuit 2, a phase modulation circuit 3, and a three-way signal output interface.
Defining three-way signal output interfaces as a first output interface 4, a second output interface 5 and a third output interface 6.
The ripple signal generation circuit 1 preferably employs a sine wave signal generation circuit or a cosine wave signal generation circuit. The sine wave or cosine wave signal generating circuit can adopt the existing sine wave or cosine wave signal generating circuit.
The ripple signal generation circuit 1 functions to generate a sine wave or cosine wave signal.
The signal output terminal of the wobble signal generating circuit 1 is connected to the first output interface 4, one signal input terminal of the signal synthesizing circuit 2 and the signal input terminal of the phase modulating circuit 3, respectively.
The signal output end of the phase modulation circuit 3 is respectively connected to the other signal input end of the signal synthesis circuit 2 and the second output interface 5.
The signal output of the signal combination circuit 2 is connected to the third output interface 6.
Taking the example of the generation of a sine wave signal by the ripple signal generation circuit 1:
the wave signal generating circuit 1 generates a sine wave and is divided into three paths which are completely the same, wherein one path is output through the first output interface 4, the other path enters the signal synthesizing circuit 2 after passing through the phase modulation circuit 3.
The phase modulation circuit 3 is used for adjusting the phase of one of the sinusoidal waves and inputting the sinusoidal wave after phase adjustment to the signal synthesis circuit 2. The signal synthesis circuit 2 synthesizes the two input sine waves to obtain a synthesized waveform.
The sine wave after phase adjustment by the phase adjusting circuit 3 is output by the second output interface 5, and the waveform synthesized by the signal synthesizing circuit 2 is output by the third output interface 6.
In addition, the fluctuation superimposition demonstration instrument further includes an oscilloscope (not shown).
The first output interface 4, the second output interface 5 and the third output interface 6 are respectively connected to an oscilloscope through signal cables.
The fluctuation superposition demonstration instrument in the embodiment is convenient for observing the process that the synthetic signal changes along with the phase difference of the input signal in real time by respectively outputting the two paths of sine wave signals and the synthetic signal and externally connecting the two paths of sine wave signals and the synthetic signal to the oscilloscope.
The utility model can be used for fluctuation superposition demonstration without holding by hand, thereby reducing the artificial participation process, ensuring the lasting demonstration time and ensuring the repeatability of the experiment; furthermore, the utility model discloses also can guarantee stable observation standing wave phenomenon in the experiment.
The signal synthesizing circuit 2 preferably employs an adder circuit.
In which the adder circuit is a known circuit, fig. 3 shows a common adder circuit structure, in which Vi1And Vi2Two input signals, V, for an adder circuitoR1-R4 are external resistors, which are the output signals of the adder circuit.
The phase modulation circuit 3 may also be a mature phase modulation circuit such as a variable phase modulation circuit. A common phase-variable phase-shift modulation circuit is shown in fig. 4, and as can be seen from fig. 4, the circuit is a tuning loop composed of a varactor diode and an inductor.
Wherein u isc(t) is a carrier signal, uΩ(t) is the input signal, C1-C4Is a capacitor, R1-R4Is a resistor, L is an inductor, CjFor variable capacitance diodes, u (t) is the output signal, by varying the carrier signal uc(t) phase modulation of the input signal is achieved.
It should be noted that the specific structures of the ripple signal generation circuit 1, the signal synthesis circuit 2, and the phase modulation circuit 3 are merely exemplary, and are for convenience of description.
Of course, the present invention may also adopt other existing and conceivable specific configurations of the ripple signal generation circuit 1, the signal synthesis circuit 2, and the phase modulation circuit 3, and the present invention is not limited to this.
The utility model discloses a make up fluctuation signal generating circuit 1, signal synthesis circuit 2 and phase modulation circuit 3, cooperate oscilloscope display simultaneously, can demonstrate two results before the ripples stack, after stack and the stack betterly.
As shown in fig. 1, the fluctuation superimposition demonstration instrument in the present embodiment further includes a housing 7.
The ripple signal generation circuit 1, the signal synthesis circuit 2, and the phase modulation circuit 3 are all located in the housing 7. And through holes, namely through holes 8, 9 and 10 are respectively arranged at the positions, corresponding to the three signal output interfaces, of the shell 7.
The phase modulation circuit 3 is provided with a phase modulation knob 11 for realizing the phase modulation of the signal input into the phase modulation circuit. The phase modulation knob 11, and the connection relationship between the phase modulation circuit 3 and the phase modulation knob 11 are also known structures, and are not described herein again.
A knob hole 12 is arranged on the shell 7 corresponding to the position of the phase adjusting knob 11, and the phase adjusting knob extends out of the knob hole.
In addition, the wave superimposition demonstrator comprises a power supply circuit (not shown) located in the housing 7. The power supply circuit is connected with the fluctuation signal generating circuit 1, the signal synthesizing circuit 2 and the phase modulating circuit 3 through power supply lines.
The power supply circuit supplies power to the ripple signal generation circuit 1, the signal synthesis circuit 2, and the phase modulation circuit 3.
The operation process of the fluctuation superposition demonstration instrument in the embodiment is as follows:
the demonstrator is powered on, the three-path signal output interfaces are respectively connected to the three-path oscilloscope, the phase modulation knob 11 is adjusted, and the two-path fluctuation signals before superposition and the signals after superposition can be intuitively demonstrated on the oscilloscope.
The utility model discloses not only can demonstrate the result that the standing wave formed, can also demonstrate the wave form before the synthesis and synthetic process.
Of course, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment, and it should be noted that any equivalent substitution, obvious modification made by those skilled in the art under the teaching of the present specification fall within the essential scope of the present specification, and the protection of the present invention should be protected.